Effect of sugar dosage on setting time, microstructure and strength of Type I and Type V Portland cements

The work presented in this paper was aimed to study the influence of sugar dosage on the setting time and strength of two types of Portland cements (Type I and Type V) widely used in Saudi Arabia, leading towards selection of an optimal dosage of sugar as an alternative set retarder. Paste and mortar specimens were prepared with different dosages of sugar and tested for initial and final setting times, compressive strength and microstructural examination of set cements. The morphology of sugar-admixed mortar specimens was studied by utilizing a scanning electron microscope. It was noted that the addition of up to 0.05% sugar by weight of cement increased the setting time sharply, however, a further addition of sugar decreased the setting time of both types of cements. Strength of the mortar specimens, particularly at an early age, decreased with an increase in sugar content. Overall results of this study indicate that, for avoiding adverse effects on setting time and strength, dosage of sugar should be in the range of 0.05–0.1% by weight of both types of cements considered in the present case study.